/*
 * Copyright 2001-2004 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.commons.logging.impl;

import java.io.Serializable;
import java.util.logging.Level;
import java.util.logging.Logger;

import org.apache.commons.logging.Log;

/**
 * <p>
 * Implementation of the <code>org.apache.commons.logging.Log</code> interface
 * that wraps the standard JDK logging mechanisms that were introduced in the
 * Merlin release (JDK 1.4).
 * </p>
 * 
 * @author <a href="mailto:sanders@apache.org">Scott Sanders</a>
 * @author <a href="mailto:bloritsch@apache.org">Berin Loritsch</a>
 * @author <a href="mailto:donaldp@apache.org">Peter Donald</a>
 * @version $Revision: 370652 $ $Date: 2006-01-19 22:23:48 +0000 (Thu, 19 Jan
 *          2006) $
 */

public class Jdk14Logger implements Log, Serializable {

    private static final long serialVersionUID = 4784713551416303804L;

    /**
     * This member variable simply ensures that any attempt to initialise this
     * class in a pre-1.4 JVM will result in an ExceptionInInitializerError. It
     * must not be private, as an optimising compiler could detect that it is
     * not used and optimise it away.
     */
    protected static final Level dummyLevel = Level.FINE;

    // ----------------------------------------------------------- Constructors

    /**
     * Construct a named instance of this Logger.
     * 
     * @param name
     *            Name of the logger to be constructed
     */
    public Jdk14Logger(String name) {

        this.name = name;
        logger = getLogger();

    }

    // ----------------------------------------------------- Instance Variables

    /**
     * The underlying Logger implementation we are using.
     */
    protected transient Logger logger = null;

    /**
     * The name of the logger we are wrapping.
     */
    protected String name = null;

    // --------------------------------------------------------- Public Methods

    private void log(Level level, String msg, Throwable ex) {

        Logger logger = getLogger();
        if (logger.isLoggable(level)) {
            // Hack (?) to get the stack trace.
            Throwable dummyException = new Throwable();
            StackTraceElement locations[] = dummyException.getStackTrace();
            // Caller will be the third element
            String cname = "unknown";
            String method = "unknown";
            if (locations != null && locations.length > 2) {
                StackTraceElement caller = locations[2];
                cname = caller.getClassName();
                method = caller.getMethodName();
            }
            if (ex == null) {
                logger.logp(level, cname, method, msg);
            } else {
                logger.logp(level, cname, method, msg, ex);
            }
        }

    }

    /**
     * Logs a message with <code>java.util.logging.Level.FINE</code>.
     * 
     * @param message
     *            to log
     * @see org.apache.commons.logging.Log#debug(Object)
     */
    public void debug(Object message) {
        log(Level.FINE, String.valueOf(message), null);
    }

    /**
     * Logs a message with <code>java.util.logging.Level.FINE</code>.
     * 
     * @param message
     *            to log
     * @param exception
     *            log this cause
     * @see org.apache.commons.logging.Log#debug(Object, Throwable)
     */
    public void debug(Object message, Throwable exception) {
        log(Level.FINE, String.valueOf(message), exception);
    }

    /**
     * Logs a message with <code>java.util.logging.Level.SEVERE</code>.
     * 
     * @param message
     *            to log
     * @see org.apache.commons.logging.Log#error(Object)
     */
    public void error(Object message) {
        log(Level.SEVERE, String.valueOf(message), null);
    }

    /**
     * Logs a message with <code>java.util.logging.Level.SEVERE</code>.
     * 
     * @param message
     *            to log
     * @param exception
     *            log this cause
     * @see org.apache.commons.logging.Log#error(Object, Throwable)
     */
    public void error(Object message, Throwable exception) {
        log(Level.SEVERE, String.valueOf(message), exception);
    }

    /**
     * Logs a message with <code>java.util.logging.Level.SEVERE</code>.
     * 
     * @param message
     *            to log
     * @see org.apache.commons.logging.Log#fatal(Object)
     */
    public void fatal(Object message) {
        log(Level.SEVERE, String.valueOf(message), null);
    }

    /**
     * Logs a message with <code>java.util.logging.Level.SEVERE</code>.
     * 
     * @param message
     *            to log
     * @param exception
     *            log this cause
     * @see org.apache.commons.logging.Log#fatal(Object, Throwable)
     */
    public void fatal(Object message, Throwable exception) {
        log(Level.SEVERE, String.valueOf(message), exception);
    }

    /**
     * Return the native Logger instance we are using.
     */
    public Logger getLogger() {
        if (logger == null) {
            logger = Logger.getLogger(name);
        }
        return (logger);
    }

    /**
     * Logs a message with <code>java.util.logging.Level.INFO</code>.
     * 
     * @param message
     *            to log
     * @see org.apache.commons.logging.Log#info(Object)
     */
    public void info(Object message) {
        log(Level.INFO, String.valueOf(message), null);
    }

    /**
     * Logs a message with <code>java.util.logging.Level.INFO</code>.
     * 
     * @param message
     *            to log
     * @param exception
     *            log this cause
     * @see org.apache.commons.logging.Log#info(Object, Throwable)
     */
    public void info(Object message, Throwable exception) {
        log(Level.INFO, String.valueOf(message), exception);
    }

    /**
     * Is debug logging currently enabled?
     */
    public boolean isDebugEnabled() {
        return (getLogger().isLoggable(Level.FINE));
    }

    /**
     * Is error logging currently enabled?
     */
    public boolean isErrorEnabled() {
        return (getLogger().isLoggable(Level.SEVERE));
    }

    /**
     * Is fatal logging currently enabled?
     */
    public boolean isFatalEnabled() {
        return (getLogger().isLoggable(Level.SEVERE));
    }

    /**
     * Is info logging currently enabled?
     */
    public boolean isInfoEnabled() {
        return (getLogger().isLoggable(Level.INFO));
    }

    /**
     * Is trace logging currently enabled?
     */
    public boolean isTraceEnabled() {
        return (getLogger().isLoggable(Level.FINEST));
    }

    /**
     * Is warn logging currently enabled?
     */
    public boolean isWarnEnabled() {
        return (getLogger().isLoggable(Level.WARNING));
    }

    /**
     * Logs a message with <code>java.util.logging.Level.FINEST</code>.
     * 
     * @param message
     *            to log
     * @see org.apache.commons.logging.Log#trace(Object)
     */
    public void trace(Object message) {
        log(Level.FINEST, String.valueOf(message), null);
    }

    /**
     * Logs a message with <code>java.util.logging.Level.FINEST</code>.
     * 
     * @param message
     *            to log
     * @param exception
     *            log this cause
     * @see org.apache.commons.logging.Log#trace(Object, Throwable)
     */
    public void trace(Object message, Throwable exception) {
        log(Level.FINEST, String.valueOf(message), exception);
    }

    /**
     * Logs a message with <code>java.util.logging.Level.WARNING</code>.
     * 
     * @param message
     *            to log
     * @see org.apache.commons.logging.Log#warn(Object)
     */
    public void warn(Object message) {
        log(Level.WARNING, String.valueOf(message), null);
    }

    /**
     * Logs a message with <code>java.util.logging.Level.WARNING</code>.
     * 
     * @param message
     *            to log
     * @param exception
     *            log this cause
     * @see org.apache.commons.logging.Log#warn(Object, Throwable)
     */
    public void warn(Object message, Throwable exception) {
        log(Level.WARNING, String.valueOf(message), exception);
    }

}
